Is domestic abuse a crime?

How can a loved one who beats you up 1,000 times not be charged a crime when a stranger who beats you up can be prosecuted? perhaps he is showimg how much he loves her by beating her blue black? if a parent beats up a child,he is meting out discipline so is the guy disciplinimg his wife? why no action was taken to protect safety of a wife when she files police report of abuse? it has to reach 1,000 times first or if she drops dead ,the case is closed? How can he teach and look at the female students in the eye as a good role model?